Annual Surveillance Report 2019 Methods

1 Methodology 1.1 The National HIV Registry National surveillance for HIV notifications HIV is a notifiable disease in each state/territory health jurisdiction in Australia. All new HIV diagnoses are reported by doctors and laboratories to state/territory health authorities. Information sought on the notification forms includes: name code (based on the first two letters of the family name and the first two letters of the given name), sex, date of birth, postcode, country of birth, Aboriginal and/or Torres Strait Islander status, date of HIV diagnosis, CD4+ cell count at diagnosis, likely place of HIV acquisition, source of exposure to HIV and evidence of newly acquired HIV (see below). If the person was born overseas, language spoken at home and date of arrival in Australia are also recorded. These data are then forwarded to the Kirby Institute for collation and analysis. The database where HIV notifications are stored is referred to as the National HIV Registry. Information on country of birth has been reported by all jurisdictions since 2002 and language spoken at home has been reported by New South Wales, Queensland and Victoria since 2004 and by all jurisdictions since 2008. Information on date of arrival in Australia and likely place of acquisition has been reported by all jurisdictions since 2014. In New South Wales, information on cases of newly diagnosed HIV was sought only from the diagnosing doctor prior to 2008. From 2008, information was also sought from the doctors to whom the person with HIV was referred, and follow‑up was carried out for cases for which the information sought at HIV notification was incomplete. These new procedures resulted in more complete information on HIV notifications and reassignment of cases found to have been newly diagnosed in earlier years. The procedures used for national HIV surveillance of newly diagnosed HIV are available at kirby.unsw.edu.au. Newly acquired HIV Newly acquired HIV is defined as newly diagnosed HIV with evidence of a negative or indeterminate HIV antibody test or a diagnosis of primary HIV within the previous 12 months. Information on the date of the last negative or indeterminate test or date of onset of primary HIV has been routinely sought from each state/territory health jurisdiction since 1991. Late and advanced HIV diagnosis Advanced HIV diagnosis is defined as newly diagnosed HIV with a CD4+ cell count of less than 200 cells/μL, and late HIV diagnosis was defined as newly diagnosed HIV with a CD4+ cell count of less than 350 cells/μL. HIV notifications classified as newly acquired HIV were not categorised as late or advanced diagnoses irrespective of CD4+ cell count. Rates of HIV diagnosis Age‑standardised notification rates were calculated using population denominators obtained from the Australian Bureau of Statistics (ABS) by state, year, sex and age (ABS series 3101051‑3101058) and were standardised using ABS Standard Population data. Population denominators by country/region of birth were based on the Standard Australian Classification of Countries (SACC) (ABS series 1269.0), with proportion of population by region of birth and year ascertained from ABS.Stat data. Population denominators by year, sex, age and state for Aboriginal and Torres Strait Islander people were obtained from ABS catalogue 32380 estimated and projected population. ABS regional population denominators by age, sex, Indigenous status and state were obtained from the ABS and from the 2011 Census‑based Aboriginal and Torres Strait Islander Population Projections by Age, Sex and Remoteness Area (2011– 2026). Remoteness area categories for these data were ‘metropolitan’, ‘inner and outer regional’ and ‘remote and very remote’. State‑based proportions were assigned based on proportions by age, sex and state for each remoteness region in 2011 estimates. Rates of HIV in Aboriginal and Torres Strait Islander populations were compared with Australian‑born non‑Indigenous populations unless otherwise stated. This was done so the epidemiology excludes imported HIV cases, where trends can fluctuate in response to immigration patterns, and focuses on HIV infection endemic to Australia. High HIV‑prevalence countries Countries recognised by UNAIDS as having a national prevalence above 1% in any of the years in the past 10 years (2009–2018) were considered high‑prevalence. The following countries were considered high‑prevalence: Ukraine Lesotho South Sudan Malawi Thailand Mauritius Guyana Mozambique Suriname Namibia Belize Rwanda Antigua And Barbuda South Africa Bahamas Eswatini Barbados United Republic of Tanzania Dominican Republic Uganda Haiti Zambia Jamaica Zimbabwe Saint Vincent and the Grenadines Benin Burkina Faso Cameroon Central African Republic Chad Congo Democratic Republic of the Congo Côte d'Ivoire Equatorial Guinea Gabon Gambia Ghana Guinea Guinea-Bissau Liberia Mali Nigeria Sao Tome and Principe Sierra Leone Togo Angola Botswana Burundi Djibouti Ethiopia Kenya Australian National Notifiable Diseases Surveillance System The National Notifiable Diseases Surveillance System (NNDSS), established in 1990 under the auspices of the Communicable Diseases Network of Australia. NNDSS coordinates the national surveillance of more than 50 communicable diseases or disease groups. Under this scheme, notifications are made to the state/territory health authorities under the provisions of the public health legislation in the respective jurisdictions. Computerised, de‑identified unit records of notifications are supplied to the Australian Government Department of Health on a daily basis for collation, analysis and publication on the NNDSS website (http://www9.health.gov.au/cda/source/cda- index.cfm), updated daily, and in the quarterly journal Communicable Diseases Intelligence. Notification data provided include a unique record reference number, state or territory identifier, disease code, date of onset, date of diagnosis to the relevant health authority, sex, age, Aboriginal and Torres Strait Islander status and postcode of residence. ‘Diagnosis date’ was used to define the case specific occurence used for rate calculation. This date represents either the onset date or, where the date of onset was not known, the earliest of the specimen collection date, the notification date, and the notification receipt date. As considerable time may have elapsed between the onset and diagnosis dates for syphilis (unspecified), hepatitis B (unspecified) and hepatitis C (unspecified), the earliest of: the specimen collection date, health professional notification date or the public health unit notification receipt date was used. Viral hepatitis New notifications of viral hepatitis (hepatitis B and C) are notifiable conditions in all state/territory health jurisdictions in Australia. Cases were notified by the diagnosing laboratory, medical practitioner, hospital or a combination of these sources, through state/territory health authorities, to the National Notifiable Diseases Surveillance System (NNDSS). Age‑standardised population rates of diagnosis of viral hepatitis were calculated for each state/territory using yearly population estimates provided by the ABS as described above. Hepatitis B infection and hepatitis C infection were classified as newly acquired if evidence was available of acquisition in the 24 months prior to diagnosis. Newly acquired hepatitis B notification data were available from all health jurisdictions. Newly acquired hepatitis C notifications were available from all health jurisdictions, and in Queensland from 2010 onwards. Sexually transmissible infections Diagnoses of sexually transmissible infections were notified by state/territory health authorities to the National Notifiable Disease Surveillance System (NNDSS), maintained by the Australian Government Department of Health. Chlamydia was notifiable in all health jurisdictions except New South Wales prior to 1998. Gonorrhoea was notifiable in all health jurisdictions and infectious syphilis was notifiable in all jurisdictions since 2004. In most health jurisdictions, diagnoses of sexually transmissible infections were notified by the diagnosing laboratory, the medical practitioner, hospital or a combination of these sources (Table M1). Table M1 Source of notification of sexually transmissible infections to the National Notifiable Disease Surveillance System, by state/territory ACT NSW NT QLD SA TAS VIC WA Diagnosis Doctor Doctor Doctor Laboratory Doctor Laboratory Doctor Laboratory Doctor Doctor Hospital Laboratory Hospital Laboratory Hospital Laboratory Laboratory Gonorrhoea Laboratory Doctor Doctor Doctor Doctor Laboratory Laboratory Laboratory Laboratory Infectious Hospital Hospital Doctor Hospital Doctor Hospital Doctor Doctor syphilis Laboratory Laboratory Laboratory Laboratory Doctor Doctor Laboratory Laboratory Hospital Doctor Hospital Doctor Doctor Doctor Laboratory Laboratory Laboratory Laboratory Chlamydia Laboratory Laboratory Doctor Laboratory Not Doctor Hospital Doctor Doctor Doctor notifiable Laboratory Laboratory Laboratory Laboratory Donovanosis Laboratory Laboratory Age‑standardised rates of notification for chlamydia, gonorrhoea and infectious syphilis were calculated using analogous procedures to those described above for HIV notifications (see HIV notifications methodology). 1.2 Diagnosis and care cascade HIV diagnosis and care cascade The approach taken to develop the HIV diagnosis and care cascade was informed by recommendations from a national stakeholder reference group (see Acknowledgments for members of the

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